#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>

int max3(int a, int b, int c)
{
    if (a > b)
    {
        if (a > c)
            return a;
        else
            return c;
    }
    if (b > c)
        return b;
    else
        return c;
}
int main() {
    int a = 0, b = 0, c = 0;
    scanf("%d%d%d", &a, &b, &c);

    double x = (double)max3(a + b, b, c) / (max3(a, b + c, c) + max3(a, b, b + c));
    printf("%.2lf", x);

    return 0;
}